/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Drawing/PreviewGeometryActor.h
Add a set of triangles produced by calling TriangleGenFunc for each index in range [0,NumIndices)
void CreateOrUpdateTriangleSet ( const [FString](API\Runtime\Core\Containers\FString) & TriangleSetIdentifier, int32 NumIndices, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< void(int32[Index](API\Runtime\Chaos\Chaos\Index), [TArray](API\Runtime\Core\Containers\TArray)< [FRenderableTriangle](API\Plugins\ModelingComponents\Drawing\FRenderableTriangle) > &TrianglesOut)> TriangleGenFunc, int32 TrianglesPerIndexHint )